This invention relates to a method and apparatus for controlled handling of articles and, more particularly, to handling under high speed controlled conditions where the articles are rotated 90.degree. so as to present a different attitude for subsequent processing, and is illustrated within the environment of handling web stacks.
This invention is an improvement on co-owned U.S. Pat. No. 3,288,266 which was directed to a transfer device (cartoner loader) utilizing paddles to sweep stacks of web units such as interfolded tissue, C-folded towels, etc., about an arc so as to change stack direction and modifying the attitude or orientation relative to the center line of stack travel. A present machine operating according to the teachings of the '266 patent is limited to a range of 250-275 stacks or "clips" per minute. Above these speeds, windage becomes a problem, particularly on C-folded products where the "wings" can fold outward because of the windage and cause jam-ups in either the transfer device (carton loader), the cartoner bucket infeed conveyor, or in the cartoner itself.
The basic problem has been one where the stack or clip is not "entrapped" throughout the entire transfer cycle and the reason for the absence of positive entrapment is the difficult and previously unsolved requirement for changing direction of stack travel without changing its attitude with respect to a point in space, the requirement being necessary for proper presentation to a cartoning machine or other processing means.
Essentially, state of the art transfer speeds at 250-275 are the normal processing line limitation. Certain cartoning machines go up to 300 clips per minute but even if one were to use two cartoners in tandem for a potential 600 clips per minute, present state of the art transferring units simply cannot handle clips of these speeds because of the severity of action, the lack of product entrapment, and windage factors.
According to the present invention, the speed limitation has been overcome through a combination of conveyors utilizing gripping means which function throughout the entire transfer cycle. More particularly, web stacks are advanced along a first lineal path while being gripped by first gripping means and thereafter the first gripping means turned 90.degree. while the stacks are directed through an arcuate quadrant into a second lineal path perpendicular to the first path, the stacks remaining in the same attitude by virtue of the dual turning of the gripping means, and thereafter the stacks being gripped by second gripping means in the second path and translated into a third path for cartoning.
Other objects, advantages and details of the invention may be seen in the ensuing detailed description.